1. Field of the Invention
This invention relates to a photographic camera which uses a film cartridge having a film exit slit and a light-shielding shutter member for opening and closing the film exit slit.
2. Description of the Related Art
Recently there has been proposed a novel film cartridge in which a roll film is entirely rolled to its leading end around a spool in a cartridge body having a film exit slit and a light-shielding shutter member for opening and shutting the film exit slit. In such a film cartridge, when the film exit slit is shut, the roll film is entirely rolled around a spool to its leading end and held in a light-tight fashion and the roll film is fed out of the cartridge body and rewound into the cartridge body with the film exit slit opened.
Further there have proposed various photographic cameras which use such a novel film cartridge. Generally such a photographic camera is provided with a cartridge chamber in which the novel film cartridge is loaded, a chamber lid which opens and closes an entrance opening to the cartridge chamber, a spool drive member which is engaged with the spool of the film cartridge loaded in the cartridge chamber and rotates the spool to feed out and rewind the film from and into the cartridge body, and a shutter member opening/closing member which is engaged with the light-shielding shutter member of the film cartridge and opens and closes the film exit slit.
In such photographic cameras, however, there are various points to be improved.
For example, in such cameras, when the film cartridge is taken out from the camera after exposure, a rewind button is operated to rewind the film into the film cartridge to its leading end and the chamber lid is opened. When taking out the film cartridge, an exposure condition indicator is switched to indicate "exposed", and a mechanism for preventing the film cartridge whose exposure condition indicator is in "exposed" position from being loaded in the camera is provided to prevent double exposure.
However when the shutter release button is depressed with the rewound film cartridge kept in the cartridge chamber, the film in the film cartridge can be fed out again to cause double exposure unlike the conventional film magazine in which the film cannot be drawn out the magazine again when the film leader is once rewound into the magazine.
Further in the novel film cartridge, there is a problem that even after rewinding is completed and even if the film is not fed out the film cartridge in response to depression of the shutter release button, light can reach the film in the film cartridge upon release of the shutter so long as the light-shielding shutter member of the film cartridge is kept open unlike the conventional film magazine in which the film slit is closed by light-shielding filling after the film leader is drawn into the magazine.
Generally an ejector is provided in the cartridge chamber to lift the film cartridge by a predetermined about then the chamber lid is opened. Conventionally ejector lifts the film cartridge by an amount sufficient to disengage the spool drive member and the shutter member opening/closing member respectively from the spool and the light-shielding shutter member. Accordingly, when the film cartridge is inserted into the cartridge chamber, the film cartridge is supported by the ejector in the lifted position. From the viewpoint of easiness in loading the film cartridge, it is preferred that the film cartridge be less lifted in the lifted position so that the film cartridge can be forced into the cartridge chamber by simply closing the chamber lid without pushing the film cartridge by a finger or the like. However from the viewpoint of easiness in taking out the film cartridge, it is preferred that the film cartridge be more lifted in the lifted position.
Thus there is a demand for a film cartridge loading mechanism which enables the film cartridge to be forced into the cartridge chamber by simply closing the chamber lid and at the same time enables the film cartridge to be easily taken out from the cartridge chamber.
Further the light-shielding shutter member of the film cartridge loaded in the camera, which has been closed, must be opened when the film is to be fed out from the film cartridge for exposure and must be closed when the film cartridge is to be taken out. In view of cost, it is preferred that such opening and closing action of the light-shielding shutter member be not effected by a motor control system but be effected mechanically, for instance, in response to movement of a key member for opening and closing the chamber lid.
That is, when the film cartridge is loaded in the cartridge chamber with the light-shielding shutter member closed, said shutter member opening/closing member is engaged with a cutaway portion on the end portion of the light-shielding shutter member and when the chamber lid is closed and the key member is moved from the release position to the locking position, the shutter member opening/closing member is rotated in one direction to open the light-shielding shutter member in response to the movement of the key member. Then when the film cartridge is to be taken out, the key member is moved from the locking position to the release position and the shutter member opening/closing member is rotated in the reverse direction to close the light-shielding shutter member in response to the movement of the key member.
In such an arrangement, if the key member is not in a predetermined release position upon insertion of the film cartridge, the shutter member opening/closing member cannot be in place relative to the cutaway portion on the light-shielding shutter member and can be engaged with the cutaway portion in a wrong phase, which results in a improper opening and closing action of the light-shielding shutter member. Further when the shutter member opening/closing member is forced to be engaged with the cutaway portion in a wrong phase, one or both of them can be damaged to disable opening and closing the light-shielding shutter member.
Thus there is a demand for a mechanism which prevents the film cartridge from being loaded when the key member is not in a predetermined release position or a mechanism which holds the key member in the predetermined release position upon insertion of the film cartridge into the cartridge chamber.